Conference report on cotton insect control

Historic, archived document

Do not assume content reflects current
scientific knowledge, policies, or practices.

Bur* Ent. and Plant Quar,
U# S « Dept. Agriculture

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Stoneville, Mississippi
November 17-19, 1947

Cotton Insect Control

Conference Report

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This is a summary report of the conference held at Stoneville,
Mississippi, November 17-19, 1947, by Federal and State workers
concerned with cotton insect control. It brings together the
results of research, especially with new insecticides, for the
control of' cotton insects.

This is designed to serve as a basis for recommendations on
cotton insect control to be prepared by State agencies and
the U. S , Department of Agriculture.

This report is being distributed to research workers, extension
entomologists and to industry for their information. It is not
for general distribution,

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OEC 16 1047

INSECTICIDES FOR COTTON INSECT CONTROL

Research and extension entomologists from ten cotton- growing States and the
United States Department of Agriculture participated in a conference at the
Delta Branch Experiment Station, Stoneville, Mississippi, November 17-19,
1947, to review and summarize their experiments and experiences in cotton
insect control and to formulate a guiding statement for control recommenda¬
tions in 1948, After a review of all available information, the statement
that follows was unanimously approved.

Cultural methods of controlling cotton pests are not considered in this
statement. However, their importance cannot be too strongly emphasized.

It should be recognized that control by the use of insecticides is really
supplemental to the adoption of good farm practices. These include such
factors as early fall clean-up, seed treatment, early planting, fertiliza¬
tion, use of proper cotton varieties, proper land use, and cultivation.

These measures are influenced by climate, soil conditions, fertility, topog¬
raphy, and geographical location. It is suggested that each State prepare
its own recommendations for cotton insect control.

This statement contains recommendations for the use of certain insecticides
for the control of cotton insects. It also presents information believed
to be of value to industry in planning production programs and to cotton
growers who may be contemplating the use of some of the insecticides that
are still in an experimental stage. It contains some suggestions as to
research needs in developing a more effective cotton insect control program.
Control recommendations are presented in a general manner and are not specif¬
ically fitted to local needs. It is expected that each State will adapt to
its own conditions the information given in this summary.

In quoting this statement, material should not be removed from the context.

If the report is not reprinted in its entirety, no less than a complete sec¬
tion relating to one material or insect should be copied, and no portion of
it should be used for advertising purposes c

Benzene Hexachloride

Results obtained throughout the Cotton Belt indicated that benzene hexa¬
chloride may be useful for control of the following insects j boll weevil,
cotton aphid, cotton fleahopper, tarnished plant bug, rapid plant bug, cotton
leafworm, thrips, southern green stink bug, garden webworm, and fall armyworm.
Benzene hexachloride failed to control the bollworm and the red spider; and in
many experiments it produced conditions which resulted in a great increase in
their numbers. Benzene hexachloride killed many beneficial insects.

It has been found that accumulations in the soil of benzene hexachloride
result in an objectionable taste being imparted to some root crops, particu¬
larly potatoes and there is a possibility that this may happen in such
crops as peanuts when soil accumulations occur. Consequently, the use of
benzene hexachloride an cotton is not recommended when root crops or
peanuts are to be grown on the same soil during the next year and possibly
during the second year after application until more is known about the
hazard involved.

Results of experiments showed that a dosage of approximately one-third pound
of gamma isomer (example: 10 pounds of benzene hexa chloride dust containing
3% of the gamma isomer) per acre gave satisfactory control of the insects
named in the preceding paragraph, and that one-half pound of gamma isomer
gave a quick "knock out" of a heavy aphid population.

Tests thus far indicate that intervals between applications for boll weevil
control should be not more than 4 to 5 days. Additional information is
needed.

The following diluents have been used with satisfactory results: sulfur,
pyrophyllite , and non-alkaline clays and talcs. When 40^ sulfur was used
as a diluent with benzene hexa chi oride , serious red spider infestations did
not develop so long as the applications were continued.

Wind and convection currents greatly reduce the effectiveness of benzene hexa-
chloride for aphid control.

As a cotton insecticide, definite advantages have resulted through mixture
with other toxicants. A mixture containing 5% DDT, 3% gamma benzene hexa-
chloride plus /±0% sulfur has been especially effective.

The keeping qualities of benzene hexa chloride dusts in storage are not fully
known and need further investigation.

Cotton foliage burn has been variable. Heavy dosages of benzene hexachloride
have burned young tender leaves under certain conditions, but this was usually
of no economic importance.

The possibility of cottonseed having the taste and odor of the material fol¬
lowing applications to the plants is now under investigation.

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One season’s data, largely from Florence and Blackville, South Carolina,
indicate that quantities of benzene hexachloride equal to the amount (200
pounds) required for insect control over a 5-year period, when applied to
the soil at the time of seeding, caused no apparent injury to any of IS
different crops. Higher rates caused injury to many of these crops, espec¬
ially on very light soils, but even at the rate of 4000 pounds per acre of
3% gamma isomer, some plants survived, and these appeared to mature in a
normal manner.

Benzene hexachloride has an objectionable odor and is irritating to the eyes
and nasal passages, but further injurious effects have not been experienced
from repeated exposure of several hours at a time over a period of several
weeks. Little is known of possible cumulative effects over a longer period.
Its toxicity to birds, mammals, and fish is little known.

Further research on benzene hexachloride is needed, especially on dosages,
interval between applications, time of application, combinations with other
insecticides, mode of action on insects, relation between its use and boll-
worm and red spider build-up, effect on beneficial insects, and toxicity to
higher animals.

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Calcium Arsenate

Calcium arsenate is an economical and effective insecticide for boll weevil
and cotton leafworm control. It also gives fairly good bollworm control when
heavy poundages are used and infestations are not too heavy. Calcium arsenate
will not control the pink bollworm, cotton fleahopper, cotton aphid, common
red spider, tarnished plant bug, and rapid plant bug.

Calcium arsenate gives best control undiluted, i.e. , without an inert diluent.
It is used in dust mixtures with sulfur, rotenone, and nicotine. Mixtures
of it with some of the new insecticides such as benzene hexachloride and
(3422) diet hy 1-p- nit r oph e nyl thiophosphate have also been used. Regular cal¬
cium arsenate does not appear to be compatible with benzene hexachloride.

For boll weevil and cotton leafworm control, use at 7 to 10 pounds per acre.
For bollworm control, use 12 to 16 pounds per acre. For cotton fleahopper,
tarnished plant bug, and rapid plant bug, use 15 pounds per acre of a mixture
composed of two-thirds sulfur and one-third calcium arsenate.

Calcium arsenate in certain light soils is injurious to some crops, especially
legumes and oats. Drifting of the dust may injure soybeans and peach trees.

It is poisonous and should be handled carefully. Livestock should be kept
out of dusted fields. Care should be exercised v/hen dusting near pastures,
especially when airplanes are used. It is best to muzzle horses or mules
used in cultivating poisoned fields. Calcium arsenate has excellent dusting
qualities. It is usually available in sufficient quantities to meet normal
demands for cotton insect control.

Calcium arsenate is recommended as a standard of comparison with organic
insecticides against cotton insects for which it is effective.

Chi or da ne

Results of some field tests indicated that a 10 percent chlordane dust gave
boll weevil control equal to that of calcium arsenate , prevented an aphid
build-up, and killed weevils developing in squares. Concentrations of less
than 10% generally were not satisfactory. Red spider and bollworm infesta¬
tions increased as a result of applications at this concentration.

Results of one test indicated that a 20 percent chlordane dust may be effec¬
tive against the bollworm. In other experiments high infestations developed
after applications of this mixture were discontinued. When at least 40 per¬
cent sulfur was used in the mixture, no red spider damage occurred.

Concentrations of 10 percent or less failed to give a "knock-out" control of
aphids.

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Chlordane seems to be compatible with the non-alkaline insecticides. There
was no evidence of synergism when this material was mixed with DDT.

The toxicity of chlordane to man, animals, soil, etc., is little known, and
additional research on this phase is needed.

This material has shown promise as a cotton insecticide, but additional
research is needed to determine its effectiveness alone and in combination
with other materials to control cotton insects before it can be generally
recommended.

Commercial Mixture of 3^ Chlordane and 35o DDT

Experimental work in several States showed that a commercial mixture of 37>
chlordane and 3% DDT was inferior to calcium arsenate for control of boll
weevils when applied at 4- or 5-day intervals. It exhibited no residual
action beyond 4 or 5 days.

Cotton aphid and red spider infestations developed in some cases where the
mixture was tested.

Chlorinated Camphene

Experiments have shown that chlorinated camphene will control the following
cotton insects: boll weevil, bollworm, cotton fleahopper, thrips , cotton
leafworm, southern green stink bug, rapid plant bug, and tarnished plant bug.
Two pounds per acre of the technical material (10 pounds of 20 percent dust)
is recommended for all these pests, except the cotton fleahopper, rapid
plant bug, and tarnished plant bug, which may be controlled with 1.0 pound
of technical chlorinated camphene per acre (10 pounds of 10 percent dust).

Results indicated that satisfactory suppression of the cotton aphid was
obtained where chlorinated camphene was used throughout the season at the
rate of 2 pounds of technical material per acre, but it did not control heavy
infestations. It will not control the red spiders and may result in their
increase unless the dust contains at least 40 percent sulfur.

Chlorinated camphene kills many of the beneficial insect predators and para¬
sites, but appears to be less objectionable in this respect than most of the
other new organic insecticides. It appears to have more residual effect on
cotton than the other organic insecticides with the exception of DDT.

Non-alkaline diluents, such as pyrophyllite , sulfur, talcs, and others, are
satisfactory with chlorinated camphene. Further studies are needed on the
compatibility of this insecticide with diluents and also with other toxicants.

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No economic injury to cotton has been reported. Further tests are nec¬
essary to determine toxicity to plants and animals.

Little is known regarding the keeping qualities of chlorinated camphene in
storage other than the fact that it has been kept satisfactorily from one
dusting season until the next .

Chlorinated camphene should be kept away from food and feed and should be
handled as a poison.

It appears that this insecticide will be available in 1948 in reasonably
adequate quantities.

3422 ( 0 1 0-Diethyl- O-o-Nit rophenyl Thiophosphat e )

Experimental results -with this material were reported from several States.

The results showed that it was very effective against aphids and red
spiders at concentrations as low as 0.25 percent in some tests, and in all
tests it was effective against these insects at concentrations as low as
1 percent. In cage tests it was effective against the boll weevil at 4 per¬
cent, and against the boilworm at 5 percent. In field tests it was ineffec¬
tive against the boll weevil and the boilworm at concentrations of 2 percent.
In cage tests it was effective against stink bugs at 5 percent and the rapid
plant bug at 2 percent. In cage tests at 1 percent it was as effective as
calcium arsenate against the cotton leaf worm.

In mixtures with calcium arsenate its effectiveness appears to diminish
rather rapidly, but when mixed with organics and non-alkalirie diluents,
it appears to be stable.

This material is highly poisonous. It has a very disagreeable pungent odor,
and in some cases caused headaches, nauser , weakness, and other discomforts
to persons exposed to it for relatively short periods- Greatest precautions
should be exercised in the use or handling of this material.

Further research is needed with this insecticide both alone and mixed with
other insecticides that have shown promise for the control of cotton insects,
especially with those organic insecticides which show promise against the
boll weevil and the boilworm. Since this insecticide was the only new syn¬
thetic organic reported which controlled the red spider in field tests, it
deserves an important place in future research on this cotton pest.

Experimental work with this insecticide is too preliminary to permit recom¬
mendation for grower use.

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E-3314 - A Chlorinated Hydrocarbon

E-3314 is a product closely related to chlordane . It has been tested
against cotton insects in preliminary laboratory and cage tests only. In
such tests it was effective against adult boll weevils at a concentration
of 2.5 percent ; it had the unique property of killing a large percentage
of boll weevil larvae inside cotton squares; at 2.5 percent it was effec¬
tive against the cotton fleahopper; at 10 percent it was effective against
the cotton aphid , cotton leafworm, and stink bugs. Twenty percent concen¬
trations controlled the bollworm. It was not effective against the red
spider.

No injury to cotton foliage was noted following its use, and dust composi¬
tions with pyrophyllite had good dusting qualities and no objectionablf5 odor.
Little is known of the toxicity of this material to higher animals, and there¬
fore precautions should be observed in its use.

E3314 has been available in limited experimental quantities, and research
with it will depend upon the extent to which it becomes available. This
material is likely to be more expensive than chlordane, chlorinated camphene,
or benzene hexachloride.

DDT

DDT appears to be particularly useful for the control of the following
insects: bollworm, pink bollworm, cotton fleahopper, tarnished plant bug,
rapid plant bug, and thrips. It does not control adequately, the boll
weevil, cotton leafworm, or cotton aphid,.

In general, DDT is used as a dust for cotton insect control at concentrations
of not less than 5$ or more than 10$ either alone or in admixture with other
insecticides. A mixture successfully used on cotton contained 5$ DDT, 3$
gamma benzene hexa chloride , and approximately 40$ sulfur.

In general, 5$ DDT dusts at 10 to 15 pounds per acre have been found suffi¬
cient for control of all susceptible insects in the Southeastern States.

For Western conditions, 5 or 10$ dusts are desirable. Bollworm and pink
bollv/orm infestations require the higher rates of application; the lower
concentrations and dosages are effective for most of the other insects.

When mixed with benzene hexachloride , the dosages recommended for 5$ DDT
plus 3$ gamma benzene hexachloride are from 10 to 15 pounds per acre,
depending upon the degree of infestation, size of cotton, and other factors.
Applications on larger cotton should be not less than 10 pounds of the mix¬
ture for bollworm and pink bollworm control.

Cotton fleahoppers, plant bugs, and thrips can be adequately controlled by
10 to 15 pounds per acre of 5$ DDT dust.

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DDT 5 like calcium arsenate, often increases aphid populations to a point
where severe damage may occur unless some aphicide is included. Following
the use of DDT as a dust either alone or in combination, bollworm infesta¬
tions sometimes occur after treatments are discontinued.

In dosages recommended, DDT appears safe, but it should not be used in exces¬
sive quantities until more is known regarding possible harmful residues.

DDT appears to remain toxic to plants in light sandy soils longer than in
heavier clay soils and to lose its toxic effects more rapidly in soils con¬
taining abundant humus.

In dusting, contamination of adjacent crops from drift should be kept in
mind when such crops are to be used as food by man or animals.

The following diluents may be used in formulating DDT mixtures; sulfur,
pyrophyllite , neutral talcs, neutral clays, or other neutral or slightly
acid materials. Alkaline diluents should not be used in making DDT formula¬
tions. DDT appears to be compatible with chlordane and chlorinated camphene
and unlikely to injure cotton when used in formulations with these materials.

It may also be compatible with 3422. It is not considered compatible with
calcium arsenate unless the material is used soon after mixing.

Keeping qualities of mixtures and. formulations containing recommended dilu¬
ents appear to be excellent. Mixtures containing calcium arsenate or other
alkaline diluents may not be stable.

Parasites and predators of economic insect pests are in general susceptible
to DDT , and biological control is seriously impaired following the use of
DDT combinations or of DDT itself.

While toxicity to man and animals appears to be rather low as compared with
most inorganic insecticides now In use, caution should be exercised in hand¬
ling it. Little is known of the cumulative effects of repeated small dosages
to man or domestic animals, and for that reason it should be handled with the
same precaution as inorganic insecticides.

DDT is highly toxic to fish and amphibians, and precautions should be taken
to preclude the possibility of stream pollution.

It appears that DDT will be available in sufficient supply to meet all except
possible local shortages which result from poor distribution or unexpected
demand.

The following phases of research should be emphasized; new uses; the cause of
increase of aphid populations where DDT without aphicides is used; new mixtures
with organic and inorganic insecticides; synergistic effects of DDT and other
materials in DDT formulations; compatibility with diluents and other insecti¬
cides; toxicity, especially by comparisons of cage and field tests, and of the
effects of temperature, humidity, or other factors not immediately controllable
residual effect as indicated by toxicity to insects; and from contamination of
crops used as food by man or animals.

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‘Hexaethyl Tetraphosphate

In limited tests , hexaethyl tetraphosphate used fresh from original containers
has been shown to be very effective against several important cotton insects,
namely, aphids, red spiders, and cotton fleahoppers; but it is relatively
ineffective against the boll weevil and bollworm. However, it deteriorates
very rapidly when exposed to moist air, is incompatible with alkaline materials,
and is very toxic to warm-blooded animals. Other new materials have also shown
promise in the control of the above-named susceptible insects, and for these
reasons it is not likely that hexaethyl tetraphosphate will be given special
attention in research on cotton insects in 1948. The data available do not
justify including it in control recommendations for cotton insects.

Nicotine

Two percent of nicotine in alternate applications of calcium arsenate or 1%
nicotine in all applications of this material will prevent a cotton aphid
build-up if properly applied.

The source of nicotine may be nicotine sulphate or a fixed nicotine in dust
form. The fixed nicotine at 1-1/2% has been found equal to 2% nicotine sulphate,.

Three percent nicotine mixed with an alkaline diluent can be used to ’’knock -
out” heavy infestations of cotton aphids if properly applied.

Since the supply of nicotine is limited, other aphicides are urgently needed.

Application of nicotine-mixed dusts should be made only when the air is calm.

If applied by airplane, the plane should be flown at a low altitude, just
above the cotton plants, and swaths should not be wider than the wing spread
of the plane, usually 30 to 40 feet.

Nicotine is highly toxic and therefore should be used with proper precautions.

Rote none

In one experiment in South Carolina, calcium arsenate-nicotine, 3 % gamma
b;enzene hexachloride plus 5% DDT, and chlorinated camphene at 10 and 20$
strengths were compared for boll weevil and cotton aphid control. A mixture
of calcium arsenate and 1 percent rotenone gave greater increases in yield
than any other treatment and prevented an aphid build-up.

In 1945 mixtures containing rotenone gave greater increases in yield than
any other treatment. Sweeping records made where calcium arsenate-rot enone
mixtures were used showed that insect populations were less than that follow¬
ing any of the other treatments. This indicates that other injurious insects
may be controlled by mixtures containing calcium arsenate and rotenone. These
records indicate that additional research is needed to determine the place
rotenone may have in cotton insect control. Rotenone is coming into adequate
supply, but the cost is still relatively high.

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Ryania

Undiluted Ryania dust was more effective in controlling stink bugs than 10
percent DDT. Ryania did not give satisfactory control of the boll weevil,
cotton aphid, pink bollworm, and bollworm.

Concentrated Ryania dusts can be mixed with pyrophyllite or certain clays.
Mixtures of Ryania with pyrophyllite and certain clays have good dusting
qualities. No information is available on its compatibility with other
insecticides .

No injury to cotton.
Although it is toxic
do not persist.

other crops, or to soils
to higher animals, it is

has been reported with Ryania.
reported that toxic residues

Ryania dusts do not appear to have much promise in the field of cotton
insect control.

Sulfur

Sulfur is a useful insecticide and diluent in cotton insect control. It
should be included in dust mixtures recommended for red spider and cotton
fleahopper control. It is desirable as a diluent for other insecticides
where a non-alkaline carrier is needed. It may be used in dust mixtures
as a repressive agent for aphids. It is generally available, and the cost
is low.

”A Proprietary Boll Neevil Spray”

”In experiments in several States, a proprietary boll weevil spray which
was sold widely in 1947 failed to control any of the cotton insects or
significantly increase cotton yields. The formula of this material is
stated to be as follows:

Copper, present as basic Sulphate, as metallic 1.50$
Zinc, present as basic Sulphate, as metallic 1.25 $
Lead Arsenate, as PbHAs04 0.50$
Calcium Arsenate, as CagfAsO^g 0.40$
Pyrethrins 0.13$
Mineral Oil 21.00$
Inert Ingredients 75.22$

Total 100.00$

Total Arsenic, as metallic, not less than 0.26$; waiter soluble arsenic,
as metallic, not more than 0.10$; Lead, as metallic, not less than 0.33$.

The use of calcium arsenate and certain organic insecticides gave yields
significantly greater than this proprietary boll weevil spray.

This product has no place in cotton insect control.”

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Boll Weevil

Calcium arsenate, benzene hexachloride , chlorinated camphene, and chlordane,
when used in proper concentrations and properly applied, have proved effec¬
tive for controlling the boll weevil. In general, the organic insecticides
should be applied at the rate of 10 pounds per acre. When used with inert
diluents or sulfur, concentrations of benzene hexachloride should contain at
least 3$ gamma; chlorinated camphene, 20$; and chlordane, 10$. Mien these
insecticides are used for control of boll weevils under farm conditions,
other insect problems have to be considered. Complications involving aphids,
bollworms, and red spiders may develop when some of these insecticides are
used alone for boll weevil control.

Combinations such as 1$ to 2$ nicotine with calcium arsenate; 3$ gamma
benzene hexachloride plus 5$ DDT, with at least 40$ sulfur; and 20$ chlori¬
nated camphene with at least 40$ sulfur are recommended to farmers for gen¬
eral use.

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Control measures should be applied only when definite need is indicated.

All insecticides should be applied at intervals of 4 to 5 days until the
infestation is brought under control, which usually requires three or more
applications. Thereafter, weekly inspections should be made, and subsequent
applications made when necessary.

Bollworm

Reports indicate that the bollworm is becoming more widespread and important
as a pest of cotton throughout most States of the Cotton Belt. Causes of
outbreaks are complex, some of which are as follows:

1. Changes in cropping systems.- Reduced acreage of cotton and
increased acreage of the crops which are hosts of the bollworm,
such as alfalfa, small grains, and soybeans, are being grown.

There may be times when these serve as hosts to increase boll¬
worm populations in cotton, while at other times they may act
as trap crops, depending on time of planting, dates of maturity
of the crop, and other seasonal variations.

2. Insecticides.- Application of certain insecticides prior to moth
flight causes an increase in aphid populations and their honeydew
attracts the moths. The aphids serve as food for predators which
would otherwise feed on the bollworm eggs. Low populations of
natural enemies of bollworms resulting from use of some insecti¬
cides also allow outbreaks to develop.

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Choice of insecticides for bollworm control will be governed by several con¬
siderations, including availability, cost, and abundance of associated pests-

Most effective materials are: 20 % chlorinated camphene, 5% DDT plus 3% gamma
benzene hexachloride , and 10% DDT.

Less effective materials are: 5% DDT, calcium arsenate, lead arsenate, and
crvolite .

Where red spider control is necessary, at least 40 % of the insecticide should

be sulfur-

When DDT is used without an aphicide, a higher percentage of sulfur (at least
70%) will aid in suppressing aphids -

All dusts should be applied at the rate of 10 to 15 pounds per acre at each
application, the amount depending upon the intensity of the infestation and
size of cotton. Applications should be made at 5-day intervals until the
infestation is brought under control. The number of applications required
may vary from one to five. Applications should begin when 4 to 5 small boll-
worms are found per 100 terminals.

Special note.- Successful control of the bollworm is dependent upon TIMELINESS
of APPLICATION and thorough coverage of the cotton plant throughout the period
of injurious infestation.

Cotton Aphid

Heavy aphid infestations often follow the use of such insecticides as calcium
arsenate for boll weevil control. Injurious infestations seldom occur on
fruiting cotton unless some insecticide has been used for control of another
insect. Infestations often occur on seedling cotton.

Wind and convection currents greatly reduce the effectiveness of aphicides.

The following insecticides and combinations have controlled cotton aphids:

Two percent of nicotine in alternate applications of calcium arsenate or 1
percent of nicotine in all applications will prevent an aphid build-up if
properly applied. Three percent of nicotine dust, using either nicotine
sulphate or fixed nicotine in an alkaline diluent, will control heavy infes¬
tations of aphids if properly applied.

Eenzene hexachloride in all applications applied at the rate of one-third
pound of the gamma isomer per acre will prevent aphid increase. If used at
the rate of one-half pound of gamma isomer per acre, it will "knock out"
heavy infestations of aphids when applied under proper conditions.

The mixture of benzene hexachloride and DDT recommended for boll weevil and
bollworm control will give results equal to benzene hexachloride used alone.

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Tests indicate that a special calcium arsenate containing 1 percent gamma in
every application or special calcium arsenate containing 2 percent in alter¬
nate applications will give adequate control if applied under proper conditions.

Concentrations of 3422 as low as 1 percent controlled heavy infestations of
aphids, but additional research is needed before it can be recommended.

Chlorinated camphene and chlordane gave variable results and are less effec¬
tive than benzene hexachloride.

In some experiments rotenone has given good aphid control, but more research
is needed.

Cotton Leafworm

For many years calcium arsenate, Paris green, and lead arsenate have been
used for control of the cotton leafworm. Where 3$ gamma benzene hexachloride,
20$ chlorinated camphene, and a mixture of 3% DDT plus 3 $ gamma benzene hexa¬
chloride have been used for control of other cotton insects, these materials
have also controlled the cotton leafworm.

Materials that were highly toxic to the cotton leafworm in cage tests during
1947 were 2$ 3422, 10% E-3314? 10$ DDD, and 10$ methoxy analogue of DDT; and
field tests should be conducted with these materials.

Cotton Fleahopper, Tarnished Plant Bug, and Rapid Plant Bug

All of the new synthetic organic insecticides adequately tested have given
effective control of the cotton fleahopper, tarnished plant bug, and rapid
ple^t bug. Considering the many factors involved, such as cost, availability,
and effectiveness for other cotton insects, their preference appears to be in
the following order: chlorinated camphene 10$ plus sulfur 40$ or more; DDT 5$
plus sulfur 75$ or more ; benzene hexachloride 3$ gamma plus sulfur 40$ or more ;
sulfur; and a mixture of sulfur and calcium arsenate 2:1.

Both chlordane and 3422 have given good results against these insects, but
more extensive experiments are necessary before recommendations can be made
for their use.

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Pink Bollworm

The most effective insecticides now known for control of the pink bollworm
are: DDT 5% plus benzene hexa chloride 3% gamma; DDT 10% plus benzene hexa-
chloride 2% gamma; and DDT 10% .

Sulfur is the preferred diluent for these formulations. They should be used
at the rate of 15 pounds per acre application at weekly intervals.

To date cultural practices have been found to be the most effective method
of control of this pest.

The new synthetic organic insecticides need further testing. Hibernation,
host plant, and migration studies should be undertaken in Arizona, New Mexico,
Oklahoma, Northern Texas, and Florida. Investigations to determine the most
effective cultural practices for suppression, eradication, and prevention of
further spread in the areas in which it occurs should be undertaken.

Red Spiders

Sulfur at the rate of 15 to 20 pounds or more per acre is recommended for the
control of red spiders.

Dust mixtures of organic insecticides used against other cotton insects should
contain at least J^.0% sulfur to prevent red spider increases.

Laboratory and field tests indicated that a 1 percent 3422 dust was effective
against red spiders.

Red spiders often increase following the use of certain insecticides for control
of the boll weevil and other cotton insects, probably as a result of the destruc¬
tion of natural enemies of the mites.

Bu?~ Cat chi ng Ma chines

Numerous observations were made following the use of ,

bug-catching machines on cotton in several States. These machines collected

large numbers of insects, but the many beneficial insects taken offsets the

good that should have resulted from the collection of the injurious species.

*

A reduction in parasites and predators has at times resulted in aphid increase.

Records made in many fields where the machines were operated showed that they
caused no appreciable reduction in boll weevil infestations. Breakage of the
cotton plants became serious when plants were large enough to be in peak of
production, at which time boll weevil control is most profitable. In many
cases, the use of these machines was discontinued when boll wo evil 'infestations
became injurious, and dusting was begun.

Machines for catching boll weevils and other cotton insects are not recoim-
mended. No mechanical device has yet been found by federal or State investi¬
gators to be equal to chemical methods for controlling cotton insects.

- 14 -

Equipment for Application of Insecticides

Better equipment for the application of insecticides is needed. For its
development, close cooperation with agricultural engineers and cost special¬
ists should he maintained. The new ground dusting machines that have been
developed and not tested on cotton should be evaluated for that purpose.

When these machines are under test, the advice and criticisms of engineers
should be solicited with the view of developing more durable equipment. A
critical study should be made of each type of machine with the idea of its
adaptability to other farm uses.

In view of the need for larger plots on account of the fumigating action of
some of the organic insecticides, a small power dusting machine with removable
hoppers should be developed for field plot work.

Air velocity should be studied in all ground machines, and the boomless types
should be improved. Positive feeds and feeding apparatus with accurate cali¬
bration at all levels of hopper load should be provided for all types of
dusters.

Different types of airplanes and airplane dusting and spraying equipment
should be studied, improved, and developed for greater efficiency of dis¬
persal and deposit of insecticides.

More suitable apparatus for application of concentrated sprays should be
developed. Mist blowers, sprayers, and thermal aerosol machines should be
studied.

Research is urgently needed on all types of ground and aerial equipment for
applying insecticides on cotton.

Cotton Entomologists and Associated Technical Workers

Cotton entomologists and associated technical workers from the Agricultural
Experiment Stations and Extension Service in 10 leading cott on-growing States
and from the United States Department of Agriculture and National Cotton
Council of America who participated in the Cotton Insect Control Conference
at the Delta Branch Experiment Station, Stoneville, Mississippi, on November 17,
IS, and 19, 1947, were:

*

Alabama

F. S, Arant , Entomologist, Agricultural Experiment Station, Auburn, Ala.

W. A. Ruffin, Entomologist, Extension Service, Auburn, Ala.

Arkansas

Dwight Isely, Entomologist, Agricultural Experiment Station, Fayetteville

Ark.

Charles Lincoln, Entomologist, Agricultural Extension Service,
Fayetteville, Ark.

Georgia

P. Mo Gilmer, Entomologist, Georgia Coastal Plains Experiment Station
and BEPQ, U.S.D.A., Tifton, Ga.

Louisiana

C. E. Smith, Entomologist, Experiment .Station, Baton Rouge, La.

Jo So Roussel, Entomologist, Experiment Station, Baton Rouge, La.

W. S. McGregor, Extension Ent omologist , Baton Rouge, La.

Co B. Iiaddon, Superintendent, Experiment Station, St. Joseph, La.

Mississippi

Clay Lyle, Entomologist, Experiment Station, State Plant Board and
Dean, School of Science, State College, Miss.

A. L. Hamner, Entomologist, Agricultural Experiment Station, State Colleg
Miss .

Lo C. Murphree , Extension Entomologist , State College, Miss.

C. R. Sayre, Superintendent, Delta Branch Experiment Station, Stoneville,
Miss.

0. T. Guice, Jr., Inspector, State Plant Board of Mississippi, Stoneville
Mss.

J. B. Dick, Agronomist, Delta Branch Experiment Station and BPISAE, ARA,
U.S.D.A. , Stoneville, Miss.

W. R. Smith, Entomologist, Delta Branch Experiment Station, Stoneville,
Miss.

B. J. Young, Vice-President and Production Manager, Delta & Pine Land
C ompany , Scott, Mi s s .

J. W. Neely, Plant Breeder, Stoneville Pedigreed Seed Company, Stoneville
Miss .

North Carolina

W. M. Kulash, Entomologist, Experiment Station, Raleigh, No C.

J. W. Conner, Jr., Extension Entomologist, Raleigh, N. C.

Oklahoma

C. F. Stiles, Extension Entomologist, Stillwater, Oklahoma
South Carolina

W. C. Nettles, Extension Entomologist, Clemson, S. C.

Cedric H. Jordan, Jr., Assistant Extension Entomologist, Clemson, S. C.
H. G. Boylston, Cotton Specialist, Extension Service, Clemson, S. C.

J. G. Watts, Entomologist, Edisto Branch Experiment Station, Blackville,
S. C .

- 16 -

Tennessee

J. 0, Andes , Extension Plant Pathologist and Entomologist, University
of Tennessee, Knoxville, Tenn.

Texas

Ho G. Johnston, Head, Department of Entomology, Texas A. & M« College,
Agricultural Experiment Station and Extension Service, College
Station, Texas

Gaines, Entomologist, Experiment Station, College Station, Texas

fi

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C. A. King, Extension Entomologist, College Station, Texas

United States Department of Agriculture

Agricultural Research Administration

Bureau of Entomology and Plant Quarantine

F. C. Bishopp, Assistant Chief, Washington, D. C.

Ho L. Haller, Assistant to the Chief, Washington, Do C.

R. Wo Harned, Division of Cotton Insects, Washington, D. C.

Gaines

Young

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Bureau of Plant Industry, Soils, and Agricultural Engineering
Jo E. Hite, Cotton Specialist, Jackson, Miss.

Sidney G. Brain, Plant Breeder, Stoneville, Miss.

Office of Experiment Stations

Eo R. McGovran, Entomologist, Washington, D. C.

Extension Service

M. F. Jones, Entomologist, Washington, D. C.

National Cotton Council of America

Clifton Kirkpatrick, Director, Production Section, Production
and Marketing Division, Memphis, Tenn.

St one ville , Mi s si s sippi
November 24, 194V